A refrigerant fluid circuit of this type is known from French patent specification FR 2 717 126 A. In this known circuit, fluid switching means are also provided for selectively passing fluid from the first branch either into the second branch or into the third branch, means also being provided for delivery into the cabin of the vehicle air which has undergone heat exchange with the evaporator.
The above mentioned fluid switching means commonly comprises two three-way electromechanical valves. They enable the circuit to be put into three different configurations, in which it operates, respectively, as a conventional air conditioning circuit, a heating circuit and, in the third configuration, in a particular mode in which the refrigerant fluid is accumulated in the evaporator.
A disadvantage of such a circuit of known type is that it requires a large number of components, which is detrimental to standardisation, and which also increases the size of the installation.